Electrochemical properties of Pb-0.6 wt% Ag powder-pressed alloy in sulfuric acid electrolyte containing Cl⁻/Mn²⁺ ions

In this study, Pb-0.6 wt% Ag powder-pressed alloy was fabricated and used as an insoluble anode for zinc electrowinning. The micromorphology, phase composition and elements distribution of the oxide layer formed on Pb-0.6 wt% Ag anode were studied. Additionally, the anodic reaction process, galvanostatic potential and oxygen evolution kinetics in Cl⁻/Mn²⁺ ions containing sulfuric acid electrolyte were investigated. Compared with the traditional Pb-0.6 wt% Ag cast-rolled alloy, Pb-0.6 wt% Ag powder-pressed alloy shows much lower anodic potential, self-corrosion current density, cell voltage and higher exchange current density in the same electrolyte. Due to a thin and uniform MnO₂ layer formed on the surface of powder-pressed alloy with the presence of Mn²⁺ ion in the electrolyte, the powder-pressed alloy presents a stable anodic potential. Consequently, the corrosion of powder-pressed Pb-0.6 wt% Ag anode was suppressed and the anode slime was decreased compared with Pb-0.6 wt% Ag cast-rolled anode.